Authentication-Results Registration for Differentiating among Cryptographic Results
RFC 6008
Document | Type |
RFC - Proposed Standard
(September 2010; No errata)
Was draft-kucherawy-authres-header-b (individual in app area)
|
|
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Author | Murray Kucherawy | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6008 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Alexey Melnikov | ||
Send notices to | barryleiba@computer.org |
Internet Engineering Task Force (IETF) M. Kucherawy Request for Comments: 6008 Cloudmark, Inc. Category: Standards Track September 2010 ISSN: 2070-1721 Authentication-Results Registration for Differentiating among Cryptographic Results Abstract This memo updates the registry of properties in Authentication- Results: message header fields to allow a multiple-result report to distinguish among one or more cryptographic signatures on a message, thus associating specific results with the signatures they represent. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6008. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Kucherawy Standards Track [Page 1] RFC 6008 Auth-Results Header.b Registration September 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Keywords . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4. Definition . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 6.1. Improvement . . . . . . . . . . . . . . . . . . . . . . . . 4 6.2. Result Forgeries . . . . . . . . . . . . . . . . . . . . . 4 6.3. New Schemes with Small Signatures . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . . 5 Appendix A. Authentication-Results Example . . . . . . . . . . . . 6 A.1. Multiple DKIM Signatures with One Failure . . . . . . . . . 6 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . . 7 1. Introduction [AUTHRES] defined a new header field for electronic mail messages that presents the results of a message authentication effort in a machine-readable format. Absent from that specification was the means by which the results of two cryptographic signatures, such as those provided by [DKIM], can both have results reported in an unambiguous manner. Fortunately, [AUTHRES] created IANA registries of reporting properties, enabling an easy remedy for this problem. This memo thus registers an additional reporting property allowing a result to be associated with a specific digital signature. 2. Keywords The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [KEYWORDS]. 3. Discussion A message can contain multiple signatures of a common sender authentication mechanism, such as [DKIM]. For example, a DomainKeys Identified Mail (DKIM) signer could apply signatures using two or more different message canonicalization algorithms to determine the resistance of each to being broken in transit. Kucherawy Standards Track [Page 2] RFC 6008 Auth-Results Header.b Registration September 2010 By applying supported "ptype.property" combinations (cf. the ABNF in [AUTHRES]), a result can be associated with a given signature provided the signatures are all unique within one of the registered values (e.g., all of them had unique "header.d" or "header.i" values). This is not guaranteed, however; a single signing agent might have practical reasons for affixing multiple signatures with the same "d=" values while varying other signature parameters. ThisShow full document text